1. Field of the Invention
The present invention relates to communication devices using telephone lines, and more particularly, to a communication device using a telephone line such as a facsimile apparatus with an answering machine for a telephone that records on a magnetic tape the received information such as a message (voice signal) and facsimile data (image signal).
2. Description of the Related Art
A conventional facsimile apparatus incorporating a telephone answering machine automatically responds to a call on receiving a predetermined number of ringing bursts announcing an incoming call. A message (voice signal) or facsimile data (image signal) sent from the caller is recorded on a magnetic tape. Information regarding the received transmission, such as the order of the recorded transmission on the tape, the position where that transmission is recorded on the magnetic tape (for example, a count value of the tape), the current number of messages and facsimile data recorded on the tape, are simultaneously stored in, for example, a random access memory (RAM).
The message and facsimile data recorded on a magnetic tape is reproduced by operating an operation panel provided in the device, or by a remote telephone set through an external telephone line operated by an operator far away from the local device (remote control unit). A specific message or facsimile data can be retrieved and reproduced if a number of the order of the received transmission is specified. In reproducing a message or facsimile data, a particular position on the tape can be specified, such as skipping one succeeding message or a facsimile data, or returning to the head position of the currently reproduced message or facsimile data. Such a head position detecting operation is carried out using the count value stored in the aforementioned RAM.
The currently recorded number of messages and facsimile data on the magnetic tape is indicated by means of a LCD (Liquid Crystal Display) on an operation panel or a blinking LED (Light Emitted Diode).
In the above-described facsimile apparatus incorporating a telephone answering machine, information regarding the transmitted data such as the count value stored in the RAM (referred to as index information hereinafter) was erased (cleared) when the magnetic tape having messages and facsimile data recorded was unloaded from the device. This is because no means are provided to detect whether a magnetic tape loaded in the device is the one unloaded from the device immediately before the loading. Index information in the RAM was erased when the magnetic tape was unloaded from the device to avoid erroneous operation of the next loaded magnetic tape from carrying out a head position detecting operation according to index information of the previous loaded tape.
Therefore, even if the same magnetic tape was loaded again into the device, head position detecting operation could not be carried out, and recording would be commenced from the head position of the magnetic tape. There was a possibility that important messages and facsimile data recorded may be erased. As a result, the availability of the communication device was degraded once the tape is unloaded from the device.